Menu (ESC)

Polyethersulfone (PES)

PES is a thermoplastic, further classified as a sulfone plastic. It has a moderately high ductility and a moderately high tensile strength relative to other thermoplastics. The graph bars on the material properties cards below compare PES to: sulfone plastics (top), all thermoplastics (middle), and the entire database (bottom). The length of each bar shows the given value as a % of the largest value in the relevant set.

Mechanical Properties

Elastic (Young's, Tensile) Modulus

2.6 GPa 0.38 x 106 psi

Elongation at Break

65 %

Flexural Modulus

2.6 GPa 0.38 x 106 psi

Flexural Strength

130 MPa 18 x 103 psi

Impact Strength: Notched Izod

91 J/m 1.7 ft-lb/in

Rockwell M Hardness


Tensile Strength: Ultimate (UTS)

87 MPa 13 x 103 psi

Thermal Properties

Glass Transition Temperature

220 °C 430 °F

Heat Deflection Temperature At 1.82 MPa (264 psi)

200 °C 390 °F

Heat Deflection Temperature At 455 kPa (66 psi)

210 °C 410 °F

Specific Heat Capacity

1100 J/kg-K 0.26 BTU/lb-°F

Thermal Conductivity

0.18 W/m-K 0.1 BTU/h-ft-°F

Thermal Expansion

53 µm/m-K

Electrical Properties

Dielectric Constant (Relative Permittivity) At 1 Hz


Dielectric Constant (Relative Permittivity) At 1 MHz


Dielectric Strength (Breakdown Potential)

16 kV/mm 0.63 V/mil

Electrical Dissipation At 1 Hz


Electrical Dissipation At 1 MHz


Electrical Resistivity Order of Magnitude

15 10x Ω-m

Otherwise Unclassified Properties


1.4 g/cm3 86 lb/ft3

Limiting Oxygen Index (LOI)

36 %

Water Absorption After 24 Hours

0.34 %

Common Calculations

Stiffness to Weight: Axial

1.1 points

Stiffness to Weight: Bending

33 points

Strength to Weight: Axial

18 points

Strength to Weight: Bending

32 points

Thermal Diffusivity

0.12 m2/s

Thermal Shock Resistance

45 points

Followup Questions

Further Reading

SPI Plastics Engineering Handbook of the Society of the Plastics Industry, Inc., 5th ed., Michael L. Berins (editor), 2000

Modern Plastics Handbook, Charles A. Harper (editor), 1999

Plastics Materials, 7th ed., J. A. Brydson, 1999